首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   550954篇
  免费   302742篇
  国内免费   50253篇
耳鼻咽喉   5705篇
儿科学   9505篇
妇产科学   3933篇
基础医学   105919篇
口腔科学   8956篇
临床医学   93587篇
内科学   117197篇
皮肤病学   8254篇
神经病学   28462篇
特种医学   21247篇
外科学   65132篇
综合类   139251篇
现状与发展   78篇
一般理论   2篇
预防医学   79883篇
眼科学   21830篇
药学   94896篇
  549篇
中国医学   71906篇
肿瘤学   27657篇
  2023年   6378篇
  2022年   13624篇
  2021年   16352篇
  2020年   16812篇
  2019年   17050篇
  2018年   18006篇
  2017年   21112篇
  2016年   17701篇
  2015年   23822篇
  2014年   27230篇
  2013年   31512篇
  2012年   40828篇
  2011年   44093篇
  2010年   44348篇
  2009年   49800篇
  2008年   37987篇
  2007年   33229篇
  2006年   29718篇
  2005年   24662篇
  2004年   21157篇
  2003年   18178篇
  2002年   16280篇
  2001年   17786篇
  2000年   11582篇
  1999年   13797篇
  1998年   13921篇
  1997年   13783篇
  1996年   14872篇
  1995年   15051篇
  1994年   14826篇
  1993年   13524篇
  1992年   12743篇
  1991年   12148篇
  1990年   11117篇
  1989年   10973篇
  1988年   10517篇
  1987年   9862篇
  1986年   9392篇
  1985年   8459篇
  1984年   6535篇
  1983年   6550篇
  1982年   7607篇
  1981年   7141篇
  1980年   6808篇
  1979年   6641篇
  1978年   5817篇
  1977年   6122篇
  1976年   5744篇
  1975年   5482篇
  1974年   5034篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.  相似文献   
72.
The relative free energy of binding the anions Cl- and Br- to the macrotricyclic receptor SC24 in water has been computed by a computer simulation technique. This result and an incidental result for the relative free energy of hydration of the anions are in excellent agreement with experimental data. The simulation approach to ligand-receptor interactions that is described here has significant potential as a predictive tool in chemistry, biochemistry, and pharmacology.  相似文献   
73.
74.
75.
Performance characteristics of pooled rabbit IgG polyclonal anti-C3d are compared with one mouse IgM and three mouse IgG monoclonal anti-C3d antibodies (MAs). IgG MA,s employed singly or in combination, failed to precipitate C3d; by contrast, IgM MA and polyclonal anti-C3d precipitated C3d. Measurements of polyclonal anti-C3d concentration by chemical means and by 125I-C3d radioimmunoassay (RIA) agreed closely. RIA values were 50% of chemical measurement values for three of the four MAs. Use of sucrose density gradient ultracentrifugation to assess MA C3d/anti-C3d molar combining ratios for soluble anti-C3d/C3d was not possible because fast-sedimenting multimeric C3d/anti-C3d complexes did not form. Dissociation and competitive binding studies indicate that (1) two MAs had substantially lower affinities than the other anti-C3d antibodies, and (2) polyclonal anti-C3d recognizes more C3d epitopes than are recognized by individual MAs. The results demonstrate antigenic complexity of C3d fragment and illustrate the difficulties of predicting individual MA performance based on prior experience with polyclonal antibodies.  相似文献   
76.
Background : Severe odontogenic infections are serious potentially lethal conditions. Following the death of a patient in the authors' institution this study was initiated to determine the risk factors, management and outcome of a consecutive series of patients.
Methods : All patients admitted to the Royal Adelaide Hospital under the care of the Oral and Maxillofacial Surgery Unit with odontogenic infections in calendar year 2003 were investigated. Detailed information relative to their pre-presentation history, surgical and anaesthetic management and outcome was obtained and analysed.
Results : Forty-eight patients, 32M, 16F, average age 34.5, range 19 to 88 years were treated. All presented with pain and swelling, with 21 (44 per cent) having trismus. Forty-four (92 per cent) were as a result of dental neglect and four (8 per cent) were regular dental patients having endodontic treatment which failed. Of those known to have been treated prior to presentation, most had been on antibiotics. Most patients had aggressive surgical treatment with extraction, surgical drainage, high dose intravenous antibiotics and rehydration. The hospital stay was 3.3 (range 1–16) days. Patients requiring prolonged intubation and high dependency or intensive care (40 per cent) had longer hospitalization. No patient died and all fully recovered.
Conclusion : Severe odontogenic infections are a serious risk to the patient's health and life. Management is primarily surgical with skilled anaesthetic airway management. Antibiotics are required in high intravenous doses as an adjunct and not as a primary treatment.  相似文献   
77.

Hintergrund:  

Die nosokomiale Pneumonie gehört zu den häufigsten nosokomialen Infektionen und ist die häufigste auf der Intensivstation. Die nosokomiale Pneumonie ist mit einer signifikanten Mortalität und Morbidität assoziiert, und ihr Auftreten verschlechtert die Prognose des Patienten deutlich. Nach der Definition der DRGs auch im deutschen Krankenhaussystem ist die nosokomiale Pneumonie überwiegend Sache des Krankenhauses und kann somit nicht nur das Ergebnis der Patientenbehandlung, sondern auch das finanzielle Ergebnis des Krankenhauses beeinträchtigen.  相似文献   
78.
目的探讨继发性肝癌的手术适应证和方法。方法对52例继发性肝癌的临床病例资料进行回顾性分析。结果分别采用了左半肝切除、右半肝切除、左外叶切除、右前叶切除、右后叶切除和肝楔形切除术。术后1、3、5年的生存率分别为28.3%、19.4%和11.9%。结论对适合手术的继发性肝癌,行肝切除术可以获得满意的效果。  相似文献   
79.
Abstract   We evaluated the associations between glycemic therapies and prevalence of diabetic peripheral neuropathy (DPN) at baseline among participants in the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial on medical and revascularization therapies for coronary artery disease (CAD) and on insulin-sensitizing vs. insulin-providing treatments for diabetes. A total of 2,368 patients with type 2 diabetes and CAD was evaluated. DPN was defined as clinical examination score >2 using the Michigan Neuropathy Screening Instrument (MNSI). DPN odds ratios across different groups of glycemic therapy were evaluated by multiple logistic regression adjusted for multiple covariates including age, sex, hemoglobin A1c (HbA1c), and diabetes duration. Fifty-one percent of BARI 2D subjects with valid baseline characteristics and MNSI scores had DPN. After adjusting for all variables, use of insulin was significantly associated with DPN (OR = 1.57, 95% CI: 1.15–2.13). Patients on sulfonylurea (SU) or combination of SU/metformin (Met)/thiazolidinediones (TZD) had marginally higher rates of DPN than the Met/TZD group. This cross-sectional study in a cohort of patients with type 2 diabetes and CAD showed association of insulin use with higher DPN prevalence, independent of disease duration, glycemic control, and other characteristics. The causality between a glycemic control strategy and DPN cannot be evaluated in this cross-sectional study, but continued assessment of DPN and randomized therapies in BARI 2D trial may provide further explanations on the development of DPN.  相似文献   
80.
Reported herein is a case of obsessive–compulsive disorder with persistent and distressing musical obsessions along with other symptoms. Advanced source analysis of electroencephalographic data indicated high spectral power over the bifrontal region. The musical symptoms were resistant to pharmacotherapy but there was some reduction in frequency and duration of musical obsessions with thought-stopping technique.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号